cosmopolitan/libc/fmt/pflink.h

#ifndef COSMOPOLITAN_LIBC_FMT_PFLINK_H_
#define COSMOPOLITAN_LIBC_FMT_PFLINK_H_
#include "libc/dce.h"
#include "libc/fmt/fmts.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/unicode/unicode.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
#ifndef __STRICT_ANSI__

/**
 * @fileoverview builtin+preprocessor+linker tricks for printf/scanf.
 *
 * Your printf() function only requires that you pay for what you use.
 * These macros ensure that its code size starts at under 4kb, growing
 * to about 40kb for a fully-loaded implementation. This works best when
 * format strings are constexprs that only contain directives.
 */

#define PFLINK(...) _PFLINK(__VA_ARGS__)
#define _PFLINK(FMT, ...)                                             \
  ({                                                                  \
    if (___PFLINK(FMT, strpbrk, "faAeg")) STATIC_YOINK("__fmt_dtoa"); \
    if (___PFLINK(FMT, strpbrk, "cmrqs")) {                           \
      if (___PFLINK(FMT, strchr, '#')) STATIC_YOINK("kCp437");        \
      if (___PFLINK(FMT, strstr, "%m")) STATIC_YOINK("strerror");     \
      if (!IsTiny() && (___PFLINK(FMT, strstr, "%*") ||               \
                        ___PFLINK(FMT, strpbrk, "0123456789"))) {     \
        STATIC_YOINK("strnwidth");                                    \
        STATIC_YOINK("strnwidth16");                                  \
        STATIC_YOINK("wcsnwidth");                                    \
      }                                                               \
    }                                                                 \
    FMT;                                                              \
  })

#define SFLINK(...) _SFLINK(__VA_ARGS__)
#define _SFLINK(FMT)                   \
  ({                                   \
    if (___PFLINK(FMT, strchr, 'm')) { \
      STATIC_YOINK("malloc");          \
      STATIC_YOINK("calloc");          \
      STATIC_YOINK("free");            \
      STATIC_YOINK("__grow");          \
    }                                  \
    FMT;                               \
  })

#if __GNUC__ + 0 < 4 || defined(__llvm__)
#define ___PFLINK(FMT, FN, C) 1
#else
#define ___PFLINK(FMT, FN, C) \
  !__builtin_constant_p(FMT) || ((FMT) && __builtin_##FN(FMT, C) != NULL)
#endif

#if defined(__GNUC__) && __GNUC__ < 6
/*
 * Compilers don't understand the features we've added to the format
 * string DSL, such as c string escaping, therefore we can't use it.
 * Ideally compilers should grant us more flexibility to define DSLs
 *
 * The recommended approach to turning this back on is `CFLAGS=-std=c11`
 * which puts the compiler in __STRICT_ANSI__ mode, which Cosmopolitan
 * respects by disabling all the esoteric tuning in headers like this.
 */
#pragma GCC diagnostic ignored "-Wformat-security"
#endif /* __GNUC__ + 0 < 6 */
#else
#define PFLINK(FMT) FMT
#define SFLINK(FMT) FMT
#ifdef __GNUC__
__asm__(".section .yoink\n\t"
        "nopl\t__fmt_dtoa(%rip)\n\t"
        "nopl\tkCp437(%rip)\n\t"
        "nopl\tstrerror(%rip)\n\t"
        "nopl\tstrnwidth(%rip)\n\t"
        "nopl\tstrnwidth16(%rip)\n\t"
        "nopl\twcsnwidth(%rip)\n\t"
        "nopl\tmalloc(%rip)\n\t"
        "nopl\tcalloc(%rip)\n\t"
        "nopl\t__grow(%rip)\n\t"
        ".previous");
#else
static long __pflink(long x) {
  x |= kCp437[0];
  x |= __fmt_dtoa(0, 0, 0, 0, 0, 0);
  x |= strnwidth(0, 0, 0);
  x |= strnwidth16(0, 0, 0);
  x |= wcsnwidth(0, 0, 0);
  x |= malloc(0);
  x |= __grow(0, 0, 0, 0);
  x |= (intptr_t)strerror(0);
  x |= (intptr_t)calloc(0, 0);
  return x;
}
#endif
#endif /* __STRICT_ANSI__ */
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_FMT_PFLINK_H_ */