[review v2] Only make a nullterminated string if we need to

["Christian Biesinger (Code Review)" <gerrit at gnutoolchain-gerrit dot osci dot io>]

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/222
......................................................................

Only make a nullterminated string if we need to

As of 7bb43059820c5febb4509b15202a93efde442bc6, we no longer need
a nullterminated linkage_name to look up the entry in the hash table.

So this patch makes it so we only make the copy if the entry was
not found.

gdb/ChangeLog:

2019-10-22  Christian Biesinger  <cbiesinger@google.com>

	* symtab.c (symbol_set_names): Only make a nullterminated copy of
	linkage_name if the entry was not found and we need to demangle.

Change-Id: I183302e1f51483ff6dff0fd5c3b0f32f0f04a5d2
---
M gdb/symtab.c
1 file changed, 18 insertions(+), 17 deletions(-)



diff --git a/gdb/symtab.c b/gdb/symtab.c
index 79c5fde..65d6311 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -832,8 +832,6 @@
 		  struct objfile_per_bfd_storage *per_bfd)
 {
   struct demangled_name_entry **slot;
-  /* A 0-terminated copy of the linkage name.  */
-  const char *linkage_name_copy;
 
   if (gsymbol->language == language_ada)
     {
@@ -858,20 +856,7 @@
   if (per_bfd->demangled_names_hash == NULL)
     create_demangled_names_hash (per_bfd);
 
-  if (linkage_name[len] != '\0')
-    {
-      char *alloc_name;
-
-      alloc_name = (char *) alloca (len + 1);
-      memcpy (alloc_name, linkage_name, len);
-      alloc_name[len] = '\0';
-
-      linkage_name_copy = alloc_name;
-    }
-  else
-    linkage_name_copy = linkage_name;
-
-  struct demangled_name_entry entry (gdb::string_view (linkage_name_copy, len));
+  struct demangled_name_entry entry (gdb::string_view (linkage_name, len));
   slot = ((struct demangled_name_entry **)
 	  htab_find_slot (per_bfd->demangled_names_hash.get (),
 			  &entry, INSERT));
@@ -882,6 +867,21 @@
 	 This happens to, e.g., main.init (__go_init_main).  Cope.  */
       || (gsymbol->language == language_go && (*slot)->demangled == nullptr))
     {
+      /* A 0-terminated copy of the linkage name.  */
+      const char *linkage_name_copy;
+      if (linkage_name[len] != '\0')
+	{
+	  char *alloc_name;
+
+	  alloc_name = (char *) alloca (len + 1);
+	  memcpy (alloc_name, linkage_name, len);
+	  alloc_name[len] = '\0';
+
+	  linkage_name_copy = alloc_name;
+	}
+      else
+	linkage_name_copy = linkage_name;
+
       gdb::unique_xmalloc_ptr<char> demangled_name_ptr
 	(symbol_find_demangled_name (gsymbol, linkage_name_copy));
 
@@ -912,7 +912,8 @@
 	       obstack_alloc (&per_bfd->storage_obstack,
 			      sizeof (demangled_name_entry) + len + 1));
 	  char *mangled_ptr = reinterpret_cast<char *> (*slot + 1);
-	  strcpy (mangled_ptr, linkage_name_copy);
+	  memcpy (mangled_ptr, linkage_name, len);
+	  mangled_ptr [len] = '\0';
 	  new (*slot) demangled_name_entry
 	    (gdb::string_view (mangled_ptr, len));
 	}

-- 
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: I183302e1f51483ff6dff0fd5c3b0f32f0f04a5d2
Gerrit-Change-Number: 222
Gerrit-PatchSet: 2
Gerrit-Owner: Christian Biesinger <cbiesinger@google.com>
Gerrit-Reviewer: Christian Biesinger <cbiesinger@google.com>
Gerrit-Reviewer: Luis Machado <luis.machado@linaro.org>
Gerrit-CC: Tom Tromey <tromey@sourceware.org>
Gerrit-MessageType: newpatchset