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

source code of linux/tools/perf/util/demangle-ocaml.c