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Diffstat (limited to 'tools/perf/util/demangle-rust.c')
| -rw-r--r-- | tools/perf/util/demangle-rust.c | 269 |
1 files changed, 0 insertions, 269 deletions
diff --git a/tools/perf/util/demangle-rust.c b/tools/perf/util/demangle-rust.c deleted file mode 100644 index a659fc69f73a..000000000000 --- a/tools/perf/util/demangle-rust.c +++ /dev/null @@ -1,269 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include <string.h> -#include "debug.h" - -#include "demangle-rust.h" - -/* - * Mangled Rust symbols look like this: - * - * _$LT$std..sys..fd..FileDesc$u20$as$u20$core..ops..Drop$GT$::drop::hc68340e1baa4987a - * - * The original symbol is: - * - * <std::sys::fd::FileDesc as core::ops::Drop>::drop - * - * The last component of the path is a 64-bit hash in lowercase hex, prefixed - * with "h". Rust does not have a global namespace between crates, an illusion - * which Rust maintains by using the hash to distinguish things that would - * otherwise have the same symbol. - * - * Any path component not starting with a XID_Start character is prefixed with - * "_". - * - * The following escape sequences are used: - * - * "," => $C$ - * "@" => $SP$ - * "*" => $BP$ - * "&" => $RF$ - * "<" => $LT$ - * ">" => $GT$ - * "(" => $LP$ - * ")" => $RP$ - * " " => $u20$ - * "'" => $u27$ - * "[" => $u5b$ - * "]" => $u5d$ - * "~" => $u7e$ - * - * A double ".." means "::" and a single "." means "-". - * - * The only characters allowed in the mangled symbol are a-zA-Z0-9 and _.:$ - */ - -static const char *hash_prefix = "::h"; -static const size_t hash_prefix_len = 3; -static const size_t hash_len = 16; - -static bool is_prefixed_hash(const char *start); -static bool looks_like_rust(const char *sym, size_t len); -static bool unescape(const char **in, char **out, const char *seq, char value); - -/* - * INPUT: - * sym: symbol that has been through BFD-demangling - * - * This function looks for the following indicators: - * - * 1. The hash must consist of "h" followed by 16 lowercase hex digits. - * - * 2. As a sanity check, the hash must use between 5 and 15 of the 16 possible - * hex digits. This is true of 99.9998% of hashes so once in your life you - * may see a false negative. The point is to notice path components that - * could be Rust hashes but are probably not, like "haaaaaaaaaaaaaaaa". In - * this case a false positive (non-Rust symbol has an important path - * component removed because it looks like a Rust hash) is worse than a - * false negative (the rare Rust symbol is not demangled) so this sets the - * balance in favor of false negatives. - * - * 3. There must be no characters other than a-zA-Z0-9 and _.:$ - * - * 4. There must be no unrecognized $-sign sequences. - * - * 5. There must be no sequence of three or more dots in a row ("..."). - */ -bool -rust_is_mangled(const char *sym) -{ - size_t len, len_without_hash; - - if (!sym) - return false; - - len = strlen(sym); - if (len <= hash_prefix_len + hash_len) - /* Not long enough to contain "::h" + hash + something else */ - return false; - - len_without_hash = len - (hash_prefix_len + hash_len); - if (!is_prefixed_hash(sym + len_without_hash)) - return false; - - return looks_like_rust(sym, len_without_hash); -} - -/* - * A hash is the prefix "::h" followed by 16 lowercase hex digits. The hex - * digits must comprise between 5 and 15 (inclusive) distinct digits. - */ -static bool is_prefixed_hash(const char *str) -{ - const char *end; - bool seen[16]; - size_t i; - int count; - - if (strncmp(str, hash_prefix, hash_prefix_len)) - return false; - str += hash_prefix_len; - - memset(seen, false, sizeof(seen)); - for (end = str + hash_len; str < end; str++) - if (*str >= '0' && *str <= '9') - seen[*str - '0'] = true; - else if (*str >= 'a' && *str <= 'f') - seen[*str - 'a' + 10] = true; - else - return false; - - /* Count how many distinct digits seen */ - count = 0; - for (i = 0; i < 16; i++) - if (seen[i]) - count++; - - return count >= 5 && count <= 15; -} - -static bool looks_like_rust(const char *str, size_t len) -{ - const char *end = str + len; - - while (str < end) - switch (*str) { - case '$': - if (!strncmp(str, "$C$", 3)) - str += 3; - else if (!strncmp(str, "$SP$", 4) - || !strncmp(str, "$BP$", 4) - || !strncmp(str, "$RF$", 4) - || !strncmp(str, "$LT$", 4) - || !strncmp(str, "$GT$", 4) - || !strncmp(str, "$LP$", 4) - || !strncmp(str, "$RP$", 4)) - str += 4; - else if (!strncmp(str, "$u20$", 5) - || !strncmp(str, "$u27$", 5) - || !strncmp(str, "$u5b$", 5) - || !strncmp(str, "$u5d$", 5) - || !strncmp(str, "$u7e$", 5)) - str += 5; - else - return false; - break; - case '.': - /* Do not allow three or more consecutive dots */ - if (!strncmp(str, "...", 3)) - return false; - /* Fall through */ - case 'a' ... 'z': - case 'A' ... 'Z': - case '0' ... '9': - case '_': - case ':': - str++; - break; - default: - return false; - } - - return true; -} - -/* - * INPUT: - * sym: symbol for which rust_is_mangled(sym) returns true - * - * The input is demangled in-place because the mangled name is always longer - * than the demangled one. - */ -void -rust_demangle_sym(char *sym) -{ - const char *in; - char *out; - const char *end; - - if (!sym) - return; - - in = sym; - out = sym; - end = sym + strlen(sym) - (hash_prefix_len + hash_len); - - while (in < end) - switch (*in) { - case '$': - if (!(unescape(&in, &out, "$C$", ',') - || unescape(&in, &out, "$SP$", '@') - || unescape(&in, &out, "$BP$", '*') - || unescape(&in, &out, "$RF$", '&') - || unescape(&in, &out, "$LT$", '<') - || unescape(&in, &out, "$GT$", '>') - || unescape(&in, &out, "$LP$", '(') - || unescape(&in, &out, "$RP$", ')') - || unescape(&in, &out, "$u20$", ' ') - || unescape(&in, &out, "$u27$", '\'') - || unescape(&in, &out, "$u5b$", '[') - || unescape(&in, &out, "$u5d$", ']') - || unescape(&in, &out, "$u7e$", '~'))) { - pr_err("demangle-rust: unexpected escape sequence"); - goto done; - } - break; - case '_': - /* - * If this is the start of a path component and the next - * character is an escape sequence, ignore the - * underscore. The mangler inserts an underscore to make - * sure the path component begins with a XID_Start - * character. - */ - if ((in == sym || in[-1] == ':') && in[1] == '$') - in++; - else - *out++ = *in++; - break; - case '.': - if (in[1] == '.') { - /* ".." becomes "::" */ - *out++ = ':'; - *out++ = ':'; - in += 2; - } else { - /* "." becomes "-" */ - *out++ = '-'; - in++; - } - break; - case 'a' ... 'z': - case 'A' ... 'Z': - case '0' ... '9': - case ':': - *out++ = *in++; - break; - default: - pr_err("demangle-rust: unexpected character '%c' in symbol\n", - *in); - goto done; - } - -done: - *out = '\0'; -} - -static bool unescape(const char **in, char **out, const char *seq, char value) -{ - size_t len = strlen(seq); - - if (strncmp(*in, seq, len)) - return false; - - **out = value; - - *in += len; - *out += 1; - - return true; -} |