fix memory errors with demangled name hash

This fixes a regression that Jan pointed out.

The bug is that some names were allocated by dwarf2read on the objfile
obstack, but then passed to SYMBOL_SET_NAMES with copy_name=0.  This
violates the invariant that the names must have a lifetime tied to the
lifetime of the BFD.

The fix is to allocate names on the per-BFD obstack.

I looked at all callers, direct or indirect, of SYMBOL_SET_NAMES that
pass copy_name=0.  Note that only the ELF and DWARF readers do this;
other symbol readers were never updated (and perhaps cannot be,
depending on the details of the formats).  This is why the patch is
relatively small.

Built and regtested on x86-64 Fedora 20.

2014-06-26  Tom Tromey  <tromey@redhat.com>

	PR symtab/16902:
	* dwarf2read.c (fixup_go_packaging, dwarf2_compute_name)
	(dwarf2_physname, read_partial_die)
	(guess_partial_die_structure_name, fixup_partial_die)
	(guess_full_die_structure_name, anonymous_struct_prefix)
	(dwarf2_name): Use per-BFD obstack.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2b7e33ca3a97d869a7f87c0a9346e81be02d9ff8..115b440d7ab01a2f73a3eba90a2a02a484ce4a73 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2014-06-26  Tom Tromey  <tromey@redhat.com>
+
+       PR symtab/16902:
+       * dwarf2read.c (fixup_go_packaging, dwarf2_compute_name)
+       (dwarf2_physname, read_partial_die)
+       (guess_partial_die_structure_name, fixup_partial_die)
+       (guess_full_die_structure_name, anonymous_struct_prefix)
+       (dwarf2_name): Use per-BFD obstack.
+
 2014-06-26  Yao Qi  <yao@codesourcery.com>
 
        * dummy-frame.c (dummy_frame_sniffer): Move local variables

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index ba642566393662512b06836730497a20e2121151..fc4f7cb14719af3fc8f24346964e62fc2a154e20 100644 (file)
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -7745,9 +7745,10 @@ fixup_go_packaging (struct dwarf2_cu *cu)
   if (package_name != NULL)
     {
       struct objfile *objfile = cu->objfile;
-      const char *saved_package_name = obstack_copy0 (&objfile->objfile_obstack,
-                                                     package_name,
-                                                     strlen (package_name));
+      const char *saved_package_name
+       = obstack_copy0 (&objfile->per_bfd->storage_obstack,
+                        package_name,
+                        strlen (package_name));
       struct type *type = init_type (TYPE_CODE_MODULE, 0, 0,
                                     saved_package_name, objfile);
       struct symbol *sym;
@@ -8365,6 +8366,8 @@ dwarf2_compute_name (const char *name,
          long length;
          const char *prefix;
          struct ui_file *buf;
+         char *intermediate_name;
+         const char *canonical_name = NULL;
 
          prefix = determine_prefix (die, cu);
          buf = mem_fileopen ();
@@ -8541,19 +8544,25 @@ dwarf2_compute_name (const char *name,
                }
            }
 
-         name = ui_file_obsavestring (buf, &objfile->objfile_obstack,
-                                      &length);
+         intermediate_name = ui_file_xstrdup (buf, &length);
          ui_file_delete (buf);
 
          if (cu->language == language_cplus)
-           {
-             const char *cname
-               = dwarf2_canonicalize_name (name, cu,
-                                           &objfile->objfile_obstack);
+           canonical_name
+             = dwarf2_canonicalize_name (intermediate_name, cu,
+                                         &objfile->per_bfd->storage_obstack);
+
+         /* If we only computed INTERMEDIATE_NAME, or if
+            INTERMEDIATE_NAME is already canonical, then we need to
+            copy it to the appropriate obstack.  */
+         if (canonical_name == NULL || canonical_name == intermediate_name)
+           name = obstack_copy0 (&objfile->per_bfd->storage_obstack,
+                                 intermediate_name,
+                                 strlen (intermediate_name));
+         else
+           name = canonical_name;
 
-             if (cname != NULL)
-               name = cname;
-           }
+         xfree (intermediate_name);
        }
     }
 
@@ -8562,7 +8571,7 @@ dwarf2_compute_name (const char *name,
 
 /* Return the fully qualified name of DIE, based on its DW_AT_name.
    If scope qualifiers are appropriate they will be added.  The result
-   will be allocated on the objfile_obstack, or NULL if the DIE does
+   will be allocated on the storage_obstack, or NULL if the DIE does
    not have a name.  NAME may either be from a previous call to
    dwarf2_name or NULL.
 
@@ -8677,7 +8686,8 @@ dwarf2_physname (const char *name, struct die_info *die, struct dwarf2_cu *cu)
     retval = canon;
 
   if (need_copy)
-    retval = obstack_copy0 (&objfile->objfile_obstack, retval, strlen (retval));
+    retval = obstack_copy0 (&objfile->per_bfd->storage_obstack,
+                           retval, strlen (retval));
 
   do_cleanups (back_to);
   return retval;
@@ -15508,7 +15518,7 @@ read_partial_die (const struct die_reader_specs *reader,
            default:
              part_die->name
                = dwarf2_canonicalize_name (DW_STRING (&attr), cu,
-                                           &objfile->objfile_obstack);
+                                           &objfile->per_bfd->storage_obstack);
              break;
            }
          break;
@@ -15793,7 +15803,7 @@ guess_partial_die_structure_name (struct partial_die_info *struct_pdi,
          if (actual_class_name != NULL)
            {
              struct_pdi->name
-               = obstack_copy0 (&cu->objfile->objfile_obstack,
+               = obstack_copy0 (&cu->objfile->per_bfd->storage_obstack,
                                 actual_class_name,
                                 strlen (actual_class_name));
              xfree (actual_class_name);
@@ -15879,8 +15889,9 @@ fixup_partial_die (struct partial_die_info *part_die,
          else
            base = demangled;
 
-         part_die->name = obstack_copy0 (&cu->objfile->objfile_obstack,
-                                         base, strlen (base));
+         part_die->name
+           = obstack_copy0 (&cu->objfile->per_bfd->storage_obstack,
+                            base, strlen (base));
          xfree (demangled);
        }
     }
@@ -18557,7 +18568,7 @@ guess_full_die_structure_name (struct die_info *die, struct dwarf2_cu *cu)
                          && actual_name[actual_name_len
                                         - die_name_len - 1] == ':')
                        name =
-                         obstack_copy0 (&cu->objfile->objfile_obstack,
+                         obstack_copy0 (&cu->objfile->per_bfd->storage_obstack,
                                         actual_name,
                                         actual_name_len - die_name_len - 2);
                    }
@@ -18603,7 +18614,7 @@ anonymous_struct_prefix (struct die_info *die, struct dwarf2_cu *cu)
   if (base == NULL || base == DW_STRING (attr) || base[-1] != ':')
     return "";
 
-  return obstack_copy0 (&cu->objfile->objfile_obstack,
+  return obstack_copy0 (&cu->objfile->per_bfd->storage_obstack,
                        DW_STRING (attr), &base[-1] - DW_STRING (attr));
 }
 
@@ -18943,8 +18954,9 @@ dwarf2_name (struct die_info *die, struct dwarf2_cu *cu)
              char *base;
 
              /* FIXME: we already did this for the partial symbol... */
-             DW_STRING (attr) = obstack_copy0 (&cu->objfile->objfile_obstack,
-                                               demangled, strlen (demangled));
+             DW_STRING (attr)
+               = obstack_copy0 (&cu->objfile->per_bfd->storage_obstack,
+                                demangled, strlen (demangled));
              DW_STRING_IS_CANONICAL (attr) = 1;
              xfree (demangled);
 
@@ -18967,7 +18979,7 @@ dwarf2_name (struct die_info *die, struct dwarf2_cu *cu)
     {
       DW_STRING (attr)
        = dwarf2_canonicalize_name (DW_STRING (attr), cu,
-                                   &cu->objfile->objfile_obstack);
+                                   &cu->objfile->per_bfd->storage_obstack);
       DW_STRING_IS_CANONICAL (attr) = 1;
     }
   return DW_STRING (attr);