LXR linux/tools/perf/util/demangle-ocaml.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <string.h>
   3#include <stdlib.h>
   4#include "util/string2.h"
   5
   6#include "demangle-ocaml.h"
   7
   8#include <linux/ctype.h>
   9
  10static const char *caml_prefix = "caml";
  11static const size_t caml_prefix_len = 4;
  12
  13/* mangled OCaml symbols start with "caml" followed by an upper-case letter */
  14static bool
  15ocaml_is_mangled(const char *sym)
  16{
  17        return 0 == strncmp(sym, caml_prefix, caml_prefix_len)
  18                && isupper(sym[caml_prefix_len]);
  19}
  20
  21/*
  22 * input:
  23 *     sym: a symbol which may have been mangled by the OCaml compiler
  24 * return:
  25 *     if the input doesn't look like a mangled OCaml symbol, NULL is returned
  26 *     otherwise, a newly allocated string containing the demangled symbol is returned
  27 */
  28char *
  29ocaml_demangle_sym(const char *sym)
  30{
  31        char *result;
  32        int j = 0;
  33        int i;
  34        int len;
  35
  36        if (!ocaml_is_mangled(sym)) {
  37                return NULL;
  38        }
  39
  40        len = strlen(sym);
  41
  42        /* the demangled symbol is always smaller than the mangled symbol */
  43        result = malloc(len + 1);
  44        if (!result)
  45                return NULL;
  46
  47        /* skip "caml" prefix */
  48        i = caml_prefix_len;
  49
  50        while (i < len) {
  51                if (sym[i] == '_' && sym[i + 1] == '_') {
  52                        /* "__" -> "." */
  53                        result[j++] = '.';
  54                        i += 2;
  55                }
  56                else if (sym[i] == '$' && isxdigit(sym[i + 1]) && isxdigit(sym[i + 2])) {
  57                        /* "$xx" is a hex-encoded character */
  58                        result[j++] = (hex(sym[i + 1]) << 4) | hex(sym[i + 2]);
  59                        i += 3;
  60                }
  61                else {
  62                        result[j++] = sym[i++];
  63                }
  64        }
  65        result[j] = '\0';
  66
  67        return result;
  68}
  69