Add name splitting

The new DWARF index code works by keeping names pre-split.  That is,
rather than storing a symbol name like "a::b::c", the names "a", "b",
and "c" will be stored separately.

This patch introduces some helper code to split a full name into its
components.

1 files changed, 81 insertions, 0 deletions

diff --git a/gdb/split-name.c b/gdb/split-name.c
new file mode 100644
index 0000000..35fe0fe
--- /dev/null
+++ b/gdb/split-name.c
@@ -0,0 +1,81 @@
+/* Split a symbol name.
+
+   Copyright (C) 2022 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "split-name.h"
+#include "cp-support.h"
+
+/* See split-name.h.  */
+
+std::vector<gdb::string_view>
+split_name (const char *name, split_style style)
+{
+  std::vector<gdb::string_view> result;
+  unsigned int previous_len = 0;
+
+  switch (style)
+    {
+    case split_style::CXX:
+      for (unsigned int current_len = cp_find_first_component (name);
+	   name[current_len] != '\0';
+	   current_len += cp_find_first_component (name + current_len))
+	{
+	  gdb_assert (name[current_len] == ':');
+	  result.emplace_back (&name[previous_len],
+			       current_len - previous_len);
+	  /* Skip the '::'.  */
+	  current_len += 2;
+	  previous_len = current_len;
+	}
+      break;
+
+    case split_style::UNDERSCORE:
+      /* Handle the Ada encoded (aka mangled) form here.  */
+      for (const char *iter = strstr (name, "__");
+	   iter != nullptr;
+	   iter = strstr (iter, "__"))
+	{
+	  result.emplace_back (&name[previous_len],
+			       iter - &name[previous_len]);
+	  iter += 2;
+	  previous_len = iter - name;
+	}
+      break;
+
+    case split_style::DOT:
+      /* D and Go-style names.  */
+      for (const char *iter = strchr (name, '.');
+	   iter != nullptr;
+	   iter = strchr (iter, '.'))
+	{
+	  result.emplace_back (&name[previous_len],
+			       iter - &name[previous_len]);
+	  ++iter;
+	  previous_len = iter - name;
+	}
+      break;
+
+    default:
+      break;
+    }
+
+  result.emplace_back (&name[previous_len]);
+  return result;
+}
+