Mercurial > hg > truffle
view src/os/bsd/vm/decoder_machO.cpp @ 20295:3f2894c5052e
8048112: G1 Full GC needs to support the case when the very first region is not available
Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso
author | tschatzl |
---|---|
date | Mon, 21 Jul 2014 10:00:31 +0200 |
parents | 78bbf4d43a14 |
children |
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/* * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #ifdef __APPLE__ #include "decoder_machO.hpp" #include <cxxabi.h> #include <mach-o/loader.h> #include <mach-o/nlist.h> bool MachODecoder::demangle(const char* symbol, char *buf, int buflen) { int status; char* result; size_t size = (size_t)buflen; // Don't pass buf to __cxa_demangle. In case of the 'buf' is too small, // __cxa_demangle will call system "realloc" for additional memory, which // may use different malloc/realloc mechanism that allocates 'buf'. if ((result = abi::__cxa_demangle(symbol, NULL, NULL, &status)) != NULL) { jio_snprintf(buf, buflen, "%s", result); // call c library's free ::free(result); return true; } return false; } bool MachODecoder::decode(address addr, char *buf, int buflen, int *offset, const void *mach_base) { struct symtab_command * symt = (struct symtab_command *) mach_find_command((struct mach_header_64 *)mach_base, LC_SYMTAB); if (symt == NULL) { DEBUG_ONLY(tty->print_cr("no symtab in mach file at 0x%lx", p2i(mach_base))); return false; } uint32_t off = symt->symoff; /* symbol table offset (within this mach file) */ uint32_t nsyms = symt->nsyms; /* number of symbol table entries */ uint32_t stroff = symt->stroff; /* string table offset */ uint32_t strsize = symt->strsize; /* string table size in bytes */ // iterate through symbol table trying to match our offset uint32_t addr_relative = (uintptr_t) mach_base - (uintptr_t) addr; // offset we seek in the symtab void * symtab_addr = (void*) ((uintptr_t) mach_base + off); struct nlist_64 *cur_nlist = (struct nlist_64 *) symtab_addr; struct nlist_64 *last_nlist = cur_nlist; // no size stored in an entry, so keep previously seen nlist int32_t found_strx = 0; int32_t found_symval = 0; for (uint32_t i=0; i < nsyms; i++) { uint32_t this_value = cur_nlist->n_value; if (addr_relative == this_value) { found_strx = cur_nlist->n_un.n_strx; found_symval = this_value; break; } else if (addr_relative > this_value) { // gone past it, use previously seen nlist: found_strx = last_nlist->n_un.n_strx; found_symval = last_nlist->n_value; break; } last_nlist = cur_nlist; cur_nlist = cur_nlist + sizeof(struct nlist_64); } if (found_strx == 0) { return false; } // write the offset: *offset = addr_relative - found_symval; // lookup found_strx in the string table char * symname = mach_find_in_stringtable((char*) ((uintptr_t)mach_base + stroff), strsize, found_strx); if (symname) { strncpy(buf, symname, buflen); return true; } DEBUG_ONLY(tty->print_cr("no string or null string found.")); return false; } void* MachODecoder::mach_find_command(struct mach_header_64 * mach_base, uint32_t command_wanted) { // possibly verify it is a mach_header, use magic number. // commands begin immediately after the header. struct load_command *pos = (struct load_command *) mach_base + sizeof(struct mach_header_64); for (uint32_t i = 0; i < mach_base->ncmds; i++) { struct load_command *this_cmd = (struct load_command *) pos; if (this_cmd->cmd == command_wanted) { return pos; } int cmdsize = this_cmd->cmdsize; pos += cmdsize; } return NULL; } char* MachODecoder::mach_find_in_stringtable(char *strtab, uint32_t tablesize, int strx_wanted) { if (strx_wanted == 0) { return NULL; } char *strtab_end = strtab + tablesize; // find the first string, skip over the space char // (or the four zero bytes we see e.g. in libclient) if (*strtab == ' ') { strtab++; if (*strtab != 0) { DEBUG_ONLY(tty->print_cr("string table has leading space but no following zero.")); return NULL; } strtab++; } else { if ((uint32_t) *strtab != 0) { DEBUG_ONLY(tty->print_cr("string table without leading space or leading int of zero.")); return NULL; } strtab+=4; } // read the real strings starting at index 1 int cur_strx = 1; while (strtab < strtab_end) { if (cur_strx == strx_wanted) { return strtab; } // find start of next string while (*strtab != 0) { strtab++; } strtab++; // skip the terminating zero cur_strx++; } DEBUG_ONLY(tty->print_cr("string number %d not found.", strx_wanted)); return NULL; } #endif