[PATCH 03/13] gdb: modernize mangled_name_to_comp and cp_class_name_from_physname

[Simon Marchi <simon.marchi@efficios.com>]

 - Move gdb_cplus_demangle_v3_components above mangled_name_to_comp,
   removing the need for a forward declaration.

 - Use nullptr instead of NULL, and fix the indentation of a return
   statement in mangled_name_to_comp.

 - In cp_class_name_from_physname, declare variables where they are
   initialized, use bool instead of int for the loop flag, use for loops
   instead of while loops to reduce the scope of the loop variables, and
   return early when no class name is found.

Change-Id: I35be6a6907b15e353a5042e77f4fc6d168039c92
---
 gdb/cp-support.c | 95 +++++++++++++++++++++---------------------------
 1 file changed, 42 insertions(+), 53 deletions(-)

diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index 80f3f14c4086..3ddbc4083745 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -75,9 +75,6 @@ static void
 		    canonicalization_ftype *finder,
 		    void *data);
 
-static demangle_parse_info_up gdb_cplus_demangle_v3_components
-  (const char *mangled, int options);
-
 /* A convenience function to copy STRING into OBSTACK, returning a pointer
    to the newly allocated string and saving the number of bytes saved in LEN.
 
@@ -664,6 +661,25 @@ cp_canonicalize_string (const char *string)
   return us;
 }
 
+/* A wrapper for cplus_demangle_v3_components that forces
+   DMGL_VERBOSE.  */
+
+static demangle_parse_info_up
+gdb_cplus_demangle_v3_components (const char *mangled, int options)
+{
+  void *storage;
+  demangle_component *tree
+    = cplus_demangle_v3_components (mangled, options | DMGL_VERBOSE,
+				    &storage);
+  if (tree == nullptr)
+    return nullptr;
+
+  auto info = std::make_unique<demangle_parse_info> ();
+  info->tree = tree;
+  info->demangler_storage.reset (storage);
+  return info;
+}
+
 /* Convert a mangled name to a demangle_component tree.  OPTIONS is passed to
    the demangler.
 
@@ -685,18 +701,17 @@ mangled_name_to_comp (const char *mangled_name, int options)
 
   /* If it doesn't, or if that failed, then try to demangle the
      name.  */
-  gdb::unique_xmalloc_ptr<char> demangled_name = gdb_demangle (mangled_name,
-							       options);
-  if (demangled_name == NULL)
-   return NULL;
+  gdb::unique_xmalloc_ptr<char> demangled_name
+    = gdb_demangle (mangled_name, options);
+  if (demangled_name == nullptr)
+    return nullptr;
 
   /* If we could demangle the name, parse it to build the component
      tree.  */
   demangle_parse_info_up info
     = cp_demangled_name_to_comp (demangled_name.get ());
-
-  if (info == NULL)
-    return NULL;
+  if (info == nullptr)
+    return nullptr;
 
   info->demangled_name = std::move (demangled_name);
   return info;
@@ -707,20 +722,15 @@ mangled_name_to_comp (const char *mangled_name, int options)
 gdb::unique_xmalloc_ptr<char>
 cp_class_name_from_physname (const char *physname)
 {
-  gdb::unique_xmalloc_ptr<char> ret;
-  struct demangle_component *ret_comp, *prev_comp, *cur_comp;
   demangle_parse_info_up info = mangled_name_to_comp (physname, DMGL_ANSI);
-  int done;
-
   if (info == nullptr)
     return nullptr;
 
-  done = 0;
-  ret_comp = info->tree;
+  demangle_component *ret_comp = info->tree;
 
   /* First strip off any qualifiers, if we have a function or
      method.  */
-  while (!done)
+  for (bool done = false; !done;)
     switch (ret_comp->type)
       {
       case DEMANGLE_COMPONENT_CONST:
@@ -733,7 +743,7 @@ cp_class_name_from_physname (const char *physname)
 	ret_comp = d_left (ret_comp);
 	break;
       default:
-	done = 1;
+	done = true;
 	break;
       }
 
@@ -749,10 +759,9 @@ cp_class_name_from_physname (const char *physname)
   /* What we have now should be a name, possibly qualified.
      Additional qualifiers could live in the left subtree or the right
      subtree.  Find the last piece.  */
-  done = 0;
-  prev_comp = NULL;
-  cur_comp = ret_comp;
-  while (!done)
+  demangle_component *prev_comp = nullptr;
+  demangle_component *cur_comp = ret_comp;
+  for (bool done = false; !done;)
     switch (cur_comp->type)
       {
       case DEMANGLE_COMPONENT_QUAL_NAME:
@@ -766,24 +775,23 @@ cp_class_name_from_physname (const char *physname)
       case DEMANGLE_COMPONENT_DTOR:
       case DEMANGLE_COMPONENT_OPERATOR:
       case DEMANGLE_COMPONENT_EXTENDED_OPERATOR:
-	done = 1;
+	done = true;
 	break;
       default:
-	done = 1;
-	cur_comp = NULL;
+	done = true;
+	cur_comp = nullptr;
 	break;
       }
 
-  if (cur_comp != NULL && prev_comp != NULL)
-    {
-      /* We want to discard the rightmost child of PREV_COMP.  */
-      *prev_comp = *d_left (prev_comp);
-      /* The ten is completely arbitrary; we don't have a good
-	 estimate.  */
-      ret = cp_comp_to_string (ret_comp, 10);
-    }
+  if (cur_comp == nullptr || prev_comp == nullptr)
+    return nullptr;
 
-  return ret;
+  /* We want to discard the rightmost child of PREV_COMP.  */
+  *prev_comp = *d_left (prev_comp);
+
+  /* The ten is completely arbitrary; we don't have a good
+     estimate.  */
+  return cp_comp_to_string (ret_comp, 10);
 }
 
 /* Return the child of COMP which is the basename of a method,
@@ -1650,25 +1658,6 @@ gdb_cplus_demangle_print (int options,
 			   estimated_length, &allocated_size));
 }
 
-/* A wrapper for cplus_demangle_v3_components that forces
-   DMGL_VERBOSE.  */
-
-static demangle_parse_info_up
-gdb_cplus_demangle_v3_components (const char *mangled, int options)
-{
-  void *storage;
-  demangle_component *tree
-    = cplus_demangle_v3_components (mangled, options | DMGL_VERBOSE,
-				    &storage);
-  if (tree == nullptr)
-    return nullptr;
-
-  auto info = std::make_unique<demangle_parse_info> ();
-  info->tree = tree;
-  info->demangler_storage.reset (storage);
-  return info;
-}
-
 /* See cp-support.h.  */
 
 unsigned int
-- 
2.56.0