e1cb00db67
* rust-demangle.c (looks_like_rust): Remove. (rust_is_mangled): Don't check escapes. (is_prefixed_hash): Allow 0-9a-f permutations. (rust_demangle_sym): Don't bail on unknown escapes. * testsuite/rust-demangle-expected: Update 'main::$99$' test. From-SVN: r276539
323 lines
8.4 KiB
C
323 lines
8.4 KiB
C
/* Demangler for the Rust programming language
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Copyright (C) 2016-2019 Free Software Foundation, Inc.
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Written by David Tolnay (dtolnay@gmail.com).
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This file is part of the libiberty library.
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Libiberty is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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In addition to the permissions in the GNU Library General Public
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License, the Free Software Foundation gives you unlimited permission
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to link the compiled version of this file into combinations with other
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programs, and to distribute those combinations without any restriction
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coming from the use of this file. (The Library Public License
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restrictions do apply in other respects; for example, they cover
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modification of the file, and distribution when not linked into a
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combined executable.)
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Libiberty is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with libiberty; see the file COPYING.LIB.
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If not, see <http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "safe-ctype.h"
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#include <sys/types.h>
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#include <string.h>
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#include <stdio.h>
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#ifdef HAVE_STRING_H
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#include <string.h>
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#else
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extern size_t strlen(const char *s);
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extern int strncmp(const char *s1, const char *s2, size_t n);
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extern void *memset(void *s, int c, size_t n);
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#endif
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#include <demangle.h>
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#include "libiberty.h"
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#include "rust-demangle.h"
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/* Mangled (legacy) Rust symbols look like this:
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_$LT$std..sys..fd..FileDesc$u20$as$u20$core..ops..Drop$GT$::drop::hc68340e1baa4987a
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The original symbol is:
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<std::sys::fd::FileDesc as core::ops::Drop>::drop
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The last component of the path is a 64-bit hash in lowercase hex,
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prefixed with "h". Rust does not have a global namespace between
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crates, an illusion which Rust maintains by using the hash to
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distinguish things that would otherwise have the same symbol.
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Any path component not starting with a XID_Start character is
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prefixed with "_".
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The following escape sequences are used:
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"," => $C$
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"@" => $SP$
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"*" => $BP$
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"&" => $RF$
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"<" => $LT$
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">" => $GT$
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"(" => $LP$
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")" => $RP$
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"\u{XY}" => $uXY$
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A double ".." means "::" and a single "." means "-".
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The only characters allowed in the mangled symbol are a-zA-Z0-9 and _.:$ */
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static const char *hash_prefix = "::h";
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static const size_t hash_prefix_len = 3;
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static const size_t hash_len = 16;
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static int is_prefixed_hash (const char *start);
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static int parse_lower_hex_nibble (char nibble);
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static char parse_legacy_escape (const char **in);
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/* INPUT: sym: symbol that has been through C++ (gnu v3) demangling
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This function looks for the following indicators:
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1. The hash must consist of "h" followed by 16 lowercase hex digits.
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2. As a sanity check, the hash must use between 5 and 15 of the 16
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possible hex digits. This is true of 99.9998% of hashes so once
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in your life you may see a false negative. The point is to
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notice path components that could be Rust hashes but are
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probably not, like "haaaaaaaaaaaaaaaa". In this case a false
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positive (non-Rust symbol has an important path component
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removed because it looks like a Rust hash) is worse than a false
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negative (the rare Rust symbol is not demangled) so this sets
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the balance in favor of false negatives.
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3. There must be no characters other than a-zA-Z0-9 and _.:$ */
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int
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rust_is_mangled (const char *sym)
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{
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size_t len, len_without_hash;
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const char *end;
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if (!sym)
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return 0;
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len = strlen (sym);
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if (len <= hash_prefix_len + hash_len)
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/* Not long enough to contain "::h" + hash + something else */
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return 0;
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len_without_hash = len - (hash_prefix_len + hash_len);
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if (!is_prefixed_hash (sym + len_without_hash))
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return 0;
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end = sym + len_without_hash;
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while (sym < end)
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{
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if (*sym == '$' || *sym == '.' || *sym == '_' || *sym == ':'
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|| ISALNUM (*sym))
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sym++;
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else
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return 0;
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}
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return 1;
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}
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/* A hash is the prefix "::h" followed by 16 lowercase hex digits. The
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hex digits must contain at least 5 distinct digits. */
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static int
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is_prefixed_hash (const char *str)
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{
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const char *end;
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char seen[16];
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size_t i;
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int count, nibble;
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if (strncmp (str, hash_prefix, hash_prefix_len))
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return 0;
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str += hash_prefix_len;
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memset (seen, 0, sizeof(seen));
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for (end = str + hash_len; str < end; str++)
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{
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nibble = parse_lower_hex_nibble (*str);
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if (nibble < 0)
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return 0;
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seen[nibble] = 1;
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}
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/* Count how many distinct digits seen */
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count = 0;
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for (i = 0; i < 16; i++)
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if (seen[i])
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count++;
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return count >= 5;
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}
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/*
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INPUT: sym: symbol for which rust_is_mangled(sym) returned 1.
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The input is demangled in-place because the mangled name is always
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longer than the demangled one. */
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void
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rust_demangle_sym (char *sym)
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{
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const char *in;
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char *out;
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const char *end;
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char unescaped;
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if (!sym)
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return;
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in = sym;
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out = sym;
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end = sym + strlen (sym) - (hash_prefix_len + hash_len);
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while (in < end)
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{
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if (*in == '$')
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{
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unescaped = parse_legacy_escape (&in);
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if (unescaped)
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*out++ = unescaped;
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else
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/* unexpected escape sequence, skip the rest of this segment. */
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while (in < end && *in != ':')
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*out++ = *in++;
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}
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else if (*in == '_')
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{
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/* If this is the start of a path component and the next
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character is an escape sequence, ignore the underscore. The
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mangler inserts an underscore to make sure the path
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component begins with a XID_Start character. */
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if ((in == sym || in[-1] == ':') && in[1] == '$')
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in++;
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else
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*out++ = *in++;
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}
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else if (*in == '.')
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{
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if (in[1] == '.')
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{
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/* ".." becomes "::" */
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*out++ = ':';
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*out++ = ':';
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in += 2;
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}
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else
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{
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/* "." becomes "-" */
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*out++ = '-';
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in++;
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}
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}
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else if (*in == ':' || ISALNUM (*in))
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*out++ = *in++;
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else
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{
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/* unexpected character in symbol, not rust_is_mangled. */
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*out++ = '?'; /* This is pretty lame, but it's hard to do better. */
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*out = '\0';
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return;
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}
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}
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*out = '\0';
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}
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/* Return a 0x0-0xf value if the char is 0-9a-f, and -1 otherwise. */
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static int
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parse_lower_hex_nibble (char nibble)
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{
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if ('0' <= nibble && nibble <= '9')
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return nibble - '0';
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if ('a' <= nibble && nibble <= 'f')
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return 0xa + (nibble - 'a');
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return -1;
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}
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/* Return the unescaped character for a "$...$" escape, or 0 if invalid. */
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static char
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parse_legacy_escape (const char **in)
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{
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char c = 0;
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const char *e;
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size_t escape_len = 0;
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int lo_nibble = -1, hi_nibble = -1;
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if ((*in)[0] != '$')
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return 0;
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e = *in + 1;
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if (e[0] == 'C')
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{
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escape_len = 1;
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c = ',';
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}
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else
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{
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escape_len = 2;
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if (e[0] == 'S' && e[1] == 'P')
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c = '@';
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else if (e[0] == 'B' && e[1] == 'P')
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c = '*';
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else if (e[0] == 'R' && e[1] == 'F')
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c = '&';
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else if (e[0] == 'L' && e[1] == 'T')
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c = '<';
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else if (e[0] == 'G' && e[1] == 'T')
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c = '>';
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else if (e[0] == 'L' && e[1] == 'P')
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c = '(';
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else if (e[0] == 'R' && e[1] == 'P')
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c = ')';
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else if (e[0] == 'u')
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{
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escape_len = 3;
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hi_nibble = parse_lower_hex_nibble (e[1]);
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if (hi_nibble < 0)
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return 0;
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lo_nibble = parse_lower_hex_nibble (e[2]);
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if (lo_nibble < 0)
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return 0;
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/* Only allow non-control ASCII characters. */
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if (hi_nibble > 7)
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return 0;
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c = (hi_nibble << 4) | lo_nibble;
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if (c < 0x20)
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return 0;
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}
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}
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if (!c || e[escape_len] != '$')
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return 0;
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*in += 2 + escape_len;
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return c;
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}
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