src/hotspot/os/bsd/decoder_machO.cpp
changeset 47216 71c04702a3d5
parent 46560 388aa8d67c80
child 47765 b7c7428eaab9
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/bsd/decoder_machO.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,166 @@
+/*
+ * Copyright (c) 2011, 2017, 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 "prims/jvm.h"
+#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);
+      buf[buflen - 1] = '\0';
+      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
+
+