gdb: allocate subfile with new

Allocate struct subfile with new, initialize its fields instead of
memset-ing it to 0.  Use a unique_ptr for the window after a subfile has
been allocated but before it is linked in the buildsym_compunit's list
of subfile (and therefore owned by the buildsym_compunit.

I can't test the change in xcoffread.c, it's best-effort.  I couldn't
find where subfiles are freed in that file, I assume they were
intentionally (or not) leaked.

Change-Id: Ib3b6877de31b7e65bc466682f08dbf5840225f24

1 files changed, 16 insertions, 6 deletions

diff --git a/gdb/buildsym.h b/gdb/buildsym.h
index 5f0e023..50ecd33 100644
--- a/gdb/buildsym.h
+++ b/gdb/buildsym.h
@@ -45,16 +45,26 @@ struct dynamic_prop;
 
 struct subfile
 {
-  struct subfile *next;
+  subfile () = default;
+
+  /* There's nothing wrong with copying a subfile, but we don't need to, so use
+     this to avoid copying one by mistake.  */
+  DISABLE_COPY_AND_ASSIGN (subfile);
+
+  struct subfile *next = nullptr;
+
   /* Space for this is malloc'd.  */
-  char *name;
+  char *name = nullptr;
+
   /* Space for this is malloc'd.  */
-  struct linetable *line_vector;
-  int line_vector_length;
-  enum language language;
-  struct symtab *symtab;
+  struct linetable *line_vector = nullptr;
+  int line_vector_length = 0;
+  enum language language = language_unknown;
+  struct symtab *symtab = nullptr;
 };
 
+using subfile_up = std::unique_ptr<subfile>;
+
 /* Record the symbols defined for each context in a list.  We don't
    create a struct block for the context until we know how long to
    make it.  */