Fix memory leak of the demangled symbol name

compute_and_set_names would only free the name if we did not find the name
in the hashtable, but it needs to always free it.  Solve this by moving the
smart pointer outside the if.

Thanks to PhilippeW for finding this.

gdb/ChangeLog:

2020-01-09  Christian Biesinger  <cbiesinger@google.com>

	* symtab.c (general_symbol_info::compute_and_set_names): Move the
	unique_xmalloc_ptr outside the if to always free the demangled name.

Change-Id: Id7c6b8408432183700ccb5ff634818d6c5a3ac95

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b10989a410d877aaf760780db55a7464b0ba0cb7..2ba163400899378fd590faa098a5e1ba88f1e1a5 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-09  Christian Biesinger  <cbiesinger@google.com>
+
+       * symtab.c (general_symbol_info::compute_and_set_names): Move the
+       unique_xmalloc_ptr outside the if to always free the demangled name.
+
 2020-01-08  Tom Tromey  <tromey@adacore.com>
 
        * xcoffread.c (enter_line_range, read_xcoff_symtab)

diff --git a/gdb/symtab.c b/gdb/symtab.c
index 5274b88f7ab538fe1d918c40b5021d46a94de557..cdd9f2e4c12c737b74f1a7eda33111039e8a8769 100644 (file)
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -892,6 +892,16 @@ general_symbol_info::compute_and_set_names (gdb::string_view linkage_name,
           htab_find_slot_with_hash (per_bfd->demangled_names_hash.get (),
                                    &entry, *hash, INSERT));
 
+  /* The const_cast is safe because the only reason it is already
+     initialized is if we purposefully set it from a background
+     thread to avoid doing the work here.  However, it is still
+     allocated from the heap and needs to be freed by us, just
+     like if we called symbol_find_demangled_name here.  If this is
+     nullptr, we call symbol_find_demangled_name below, but we put
+     this smart pointer here to be sure that we don't leak this name.  */
+  gdb::unique_xmalloc_ptr<char> demangled_name
+    (const_cast<char *> (language_specific.demangled_name));
+
   /* If this name is not in the hash table, add it.  */
   if (*slot == NULL
       /* A C version of the symbol may have already snuck into the table.
@@ -914,15 +924,9 @@ general_symbol_info::compute_and_set_names (gdb::string_view linkage_name,
       else
        linkage_name_copy = linkage_name;
 
-      /* The const_cast is safe because the only reason it is already
-         initialized is if we purposefully set it from a background
-         thread to avoid doing the work here.  However, it is still
-         allocated from the heap and needs to be freed by us, just
-         like if we called symbol_find_demangled_name here.  */
-      gdb::unique_xmalloc_ptr<char> demangled_name
-       (language_specific.demangled_name
-        ? const_cast<char *> (language_specific.demangled_name)
-        : symbol_find_demangled_name (this, linkage_name_copy.data ()));
+      if (demangled_name.get () == nullptr)
+        demangled_name.reset
+          (symbol_find_demangled_name (this, linkage_name_copy.data ()));
 
       /* Suppose we have demangled_name==NULL, copy_name==0, and
         linkage_name_copy==linkage_name.  In this case, we already have the