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
  10 static const char *caml_prefix = "caml";
  11 static const size_t caml_prefix_len = 4;
  12
  13 /* mangled OCaml symbols start with "caml" followed by an upper-case letter */
  14 static bool
  15 ocaml_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  */
  28 char *
  29 ocaml_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 }